Tools
Tools included with the TauP package:
|
calculates travel times. |
|
calculates pierce points at model discontinuities and specified depths. |
|
calculates ray paths, depth versus epicentral distance. |
|
calculates wavefronts in steps of time, depth versus epicentral distance. |
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a GUI that incorporates the time, pierce and path tools. |
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calculates travel time curves, time versus epicentral distance. |
|
outputs travel times for a range of depths and distances in an ASCII file |
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puts theoretical arrival times into sac header variables. |
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output velocity model as a gmt script. |
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output slowness model as a gmt script. |
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textual description of the path the phase takes through the model. |
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creates a .taup model from a velocity model. |
Each tool is a Java application and has an associated wrapper to make execution easier: sh scripts for textsc{Unix} and bat files for windows. The applications are machine independent but the wrappers are OS specific. For example, to invoke TauP Time under textsc{Unix}, you could type
java -Dtaup.model.path=${TAUPPATH} edu.sc.seis.TauP.TauP Time -mod prem
or simply use the script that does the same thing,
taup time -mod prem
Each tool has a --help
flag that will print a usage summary, as well
as a --version
flag that will print the version.
TauP is moving towards a single application with subcommands, but we provide individual scripts for compatibility. These two commands produce the same result, but the first is preferred and the second style will be removed in version 3.0.
taup time -mod prem -deg 30 -ph P
taup_time -mod prem -deg 30 -ph P
Default Parameters
Each of the tools use Java Properties to allow the user to specify values
for various
parameters. The properties all have default values, which are overridden by
values from a Properties file. The tools use a text file to load the properties. It reads .taup
in the
current directory, which overwrites values read in from
.taup
in the user’s home directory. Properties may also be specified by
the --prop
command line argument.
In addition, many of the properties can be overridden by command line arguments.
The form of the properties file is very simple. Each property is set using the form begin{verbatim} taup.property.name=value end{verbatim}
one property per line.
Comment lines are allowed, and begin with a #
.
Additionally, the names of all of the properties follow a convention of
prepending ``taup.
’’ to the name of the property.
This helps to avoid name collisions when new properties
are added.
The currently used properties are: begin{description}
item[taup.model.name] the name of the initial model to be loaded, iasp91 by default. item[taup.model.path] search path for models. There is no default, but the value in the .taup file will be concatinated with any value of taup.model.path from the system properties. For example, the environment variable TAUPPATH is put into the system property taup.model.path by the wrapper shell scripts. item[taup.source.depth] initial depth of the source, 0.0 km by default. item[taup.phase.list] initial phase list, combined with taup.phase.file. The defaults are p, s, P, S, Pn, Sn, PcP, ScS, Pdiff, Sdiff, PKP, SKS, PKiKP, SKiKS, PKIKP, SKIKS. item[taup.phase.file] initial phase list, combined with taup.phase.list. There is no default value, but the default value for taup.phase.list will not be used if there is a taup.phase.file property. item[taup.depth.precision] precision for depth output, the default is 1 decimal digit.
Note that this is precision, not accuracy. Just
because you get more digits doesn’t imply that they have any meaning. item[taup.distance.precision] precision for distance output, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning. item[taup.latlon.precision] precision for latitude and longitude output, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning. item[taup.time.precision] precision for time, the default is 2 decimal digits. Note that this is precision, not accuracy. Just because you get more digits doesn’t imply that they have any meaning. item[taup.rayparam.precision] precision for ray parameter, the default is 3 decimal digits. Note that this is precision, not accuracy. Just because you get more
digits doesn’t imply that they have any meaning.
- item[taup.maxRefraction] The maximum degrees that a Pn or Sn can refract along the moho. Note this
is not the total distance, only the segment along the moho. The default is 20 degrees.
- item[taup.maxDiffraction] The maximum degrees that a Pdiff or Sdiff can diffract along the CMB.
Note this is not the total distance, only the segment along the CMB. The default is 60 degrees. item[taup.maxKmpsLaps] The maximum number of laps around the earth for
kpms style phases. Note this is the number of laps, not number of arrivals, so a value of 1 would give 2 arrivals, one going the short path and one the long way around. This can be fractional, so 0.5 would exclude the long way around path. The default is 1.
item[taup.path.maxPathInc] maximum distance in degrees between points of a path. This does a simple linear interpolant between nearby values in order to make plots look better. There is noo improvement in the accuracy of the path. item[taup.table.locsat.maxdiff] maximum distance in degrees for which Pdiff or Sdiff are put into a locsat table. Beyond this distance Pdiff and Sdiff will not be added to the table, even though they may show up in the output of TauP Time. Instead, the next later arriving phase, if any, will be used instead. The default is 105 degrees. item[taup.create.minDeltaP] Minimum difference in slowness between successive slowness samples. This is used to decide when to stop adding new samples due to the distance check. Used by TauP Create to create new models. The default is 0.1 sec/rad. item[taup.create.maxDeltaP] Maximum difference in slowness between successive slowness samples. This is used to split any layers that exceed this slowness gap. Used by TauP Create to create new models.
The default is 11.0 sec/rad.
item[taup.create.maxDepthInterval] Maximum difference between successive depth samples. This is used immediately after reading in a velocity model, with layers being split as needed. Used by TauP Create to create new models.
The default is 115 km.
item[taup.create.maxRangeInterval] Maximum difference between successive ranges, in degrees. If the difference in distance for two adjacent rays is greater than this, then a new slowness sample is inserted halfway between the two existing slowness samples. The default is 2.5 degrees. item[taup.create.maxInterpError] Maximum error for linear interpolation
between successive sample in seconds. TauP Create uses this to try to insure
that the maximum error due to linear interpolation is less than this amount. Of course, this is only an approximation based upon an estimate of the
curvature of the travel time curve for surface focus turning waves.
In particular, the error for more complicated phases is greater. For instance, if the true error for P at 30 degrees is 0.03 seconds, then the error for PP at 60 degrees would be twice that, 0.06 seconds. Used by TauP Create to create new models. The default is 0.05 seconds. item[taup.create.allowInnerCoreS] Should we allow J phases, S in the inner core? Used by TauP Create to create new models.
The default is true. Setting it to false slightly reduces storage and model
load time. end{description}
- Phase files, specified with the taup.phase.file property,
are just text files with phase names, separated by either
spaces, commas or newlines. In section ref{phasenaming} the details of
the phase naming convention are introduced.
By and large, it is compatible with traditional
seismological naming conventions, with a few additions and exceptions.
Also, for compatiblity with textit{ttimes}, you may specify
ttp
, ttp+
, tts
, tts+
,
ttbasic
or ttall
to get a phase list corresponding
to the textit{ttimes} options.